Containers having different characteristics are used today in the field of food for storing and distributing various products.
The transport of certain food products, which are marketed as refrigerated or frozen food products, requires the use of specific boxes suitable for maintaining their characteristics in a higher or lower range of temperatures.
A typical example of boxes used in these applications are expanded polystyrene boxes, formed by a body and a cover, or by two half-bodies coupled to one another, demarcating an inner space for arranging the product to be transported.
These expanded polymer material boxes have suitable waterproof and thermal insulation characteristics; however, they have the drawback that, since they have a pre-formed and fixed structure, they occupy the same volume when they are empty as they do when they are in use, which makes it difficult to store and transport them up until the moment they are used.
An alternative to these expanded polystyrene or polymer material boxes are waxed boxes, which are formed from a sheet of cardboard that is covered on at least one of its faces with a layer of wax, the purpose of which is to provide it with greater water-proofing and to prevent the cardboard from getting wet, the box losing consistency.
These waxed boxes have various drawbacks, among which are their high price and deterioration according to temperature; when the temperature is high, the wax melts and is highly inflammable; and when the temperature is very low, for example for transporting frozen products, the wax cracks and breaks, no longer performing the function of water-proofing the cardboard of the box.
There are also boxes of corrugated cardboard covered with a polyethylene (PE) film inside and nothing outside. The problem with this type of box is that, while in transit, each time it is moved from a cold-temperature chamber to inside a cold truck, boat or plane, the moisture adhered to the box turns into water penetrating inside the cardboard box affecting the structure of the box and eventually breaking. Boxes with corrugated sheet with (PE) inside and out are also available. The problem with this type of box is that it becomes excessively rigid and when assembled, many parts of the box become cracked, where moisture penetrates these cracks and again affecting the structure of the box and eventually breaking. There are also boxes with corrugated cardboard being covered with water-repellent paint inside and outside. The problem with this type of box is actually inside. Waterproof paint or varnish protects from moisture and at particular times it protects from the discrete contact of water such as rain, but it cannot withstand containing continuous amounts of water for extended periods of times. Thus, the water eventually enters the cardboard box and as with the previous boxes, affecting the structure of the box and eventually breaking. In addition, the paint or varnish used must be approved for food contact by government agencies such as the FDA.
Therefore, the technical problem that is considered is the construction of a box for food products simultaneously having the advantage of water-proofing expanded polymer material boxes, high resistance against deformation, and the advantage of transporting and storing the box in a flat configuration and assembling it when use thereof is required.
The applicant of the invention is unaware of the existence of earlier inventions which simultaneously and satisfactorily meet these requirements.